Various types of tests related to patient diagnosis and therapy can be performed by analysis assays of a sample of a patient's infections, bodily fluids or abscesses. Such patient samples are typically placed in sample vials, extracted from the vials, combined with various reagents in special reaction vessels or tubes, incubated, and analyzed to aid in treatment of the patient. In typical clinical chemical analyses, one or two assay reagents are added at separate times to a liquid sample having a known concentration, the sample-reagent combination is mixed and incubated. Interrogating measurements, turbidimetric or fluorometric or absorption readings or the like are made to ascertain end-point or rate values from which an amount of analyte may be determined, using well-known calibration techniques.
Although various known clinical analyzers for chemical, immunoassay and biological testing of samples are available, analytical clinical technology is challenged by increasing needs for improved operating cost efficiency. Due to increasing demands on clinical laboratories regarding assay throughput, new assays for additional analytes, accuracy of analytical results, and low reagent consumption, modern automated clinical analyzers have, by necessity, generally become larger, more complex and expensive. Clinical laboratories are therefore caught between the demand for increased functionality and the desire to minimize capital investments. In particular, the necessity for a clinical laboratory to reduce testing turnaround time is usually addressed by increasing analyzer throughput, regardless of the assay to be performed.
An important contributor to maintaining high throughput of automatic analyzers is the ability to quickly process a plurality of samples through a variety of different assay process and signal measurement steps. If no premium was placed on capital investment, increased throughput could be achieved by purchasing new analyzers to increase the rate of throughput. Such a solution is not generally acceptable to laboratory personnel and therefore new and improved clinical analyzers are needed with the capability to increase processing throughput with modest additional capital investment. Alternate approaches to this problem have been developed without directly addressing the concern for capital investment.
U.S. Pat. No. 5,434,083 uses a rotating reaction vessel train in which an analysis time of each of the test items is set to correspond to the number of times of circulation (number of cycles) of the reaction vessels on the reaction line. A reaction vessel renew device is selectively controlled for each reaction vessel in accordance with the number of cycles. Thus, a test item which requires a short reaction time is processed in a smaller number of cycles of the reaction line and a test item which requires a long reaction time is processed in a larger number of cycles.
U.S. Pat. No. 5,576,215 operates an analyzer so that the various devices used to perform assays of patient samples are operated in accordance with a schedule developed by a scheduler routine. The scheduler routine determines interval periods between operations performed by the devices on each biological sample as a function of an entered load list and schedules instrument system operations and the determined interval periods. The analyzer performs assays of the biological samples by operating the analyzer instrument systems in accordance with the developed schedule.
U.S. Pat. No. 5,846,491 increases throughput by employing an analyzer control system with means for allocating assay resources to one of a number of reaction vessels as a function of the time cycle for that vessel and transferring reaction vessels directly from one assay resource station to another according to a chronology selected from a plurality of different predetermined chronologies.
U.S. Pat. No. 5,985,672 also addresses the need for high-speed processing by employing a pre-processor for use in performing immunoassays on samples for analytes in the sample employing concentrically positioned incubating and processing carousels. A single transfer station permits reaction vessels containing sample and reagents to be moved between the carousels. The samples are separated, washed and mixed on the processing carousel and incubated on the incubating carousel thus speeding up processing throughput.
From this discussion of the art state in automated clinical analyzers, it may be seen that while has been considerable progress has been made toward increasing processing efficiency, there remains an unmet need for a clinical analyzer that is adapted to increase throughput in a simplified manner requiring minimal additional capital investment. In particular, there is an unmet need for a clinical analyzer in which throughput can be increased in response to increased demand at a relatively low level of capital investment.